I'm quite new with Arduino and tinkering with electronics, and I've put together a setup that I'd love some feedback on. I've attached a diagram (I know it's a Fritzing diagram, but bear with me, I'm still wrapping my head around schematic diagrams) to illustrate what I've got going on.
So, here's the gist: I've got an Arduino UNO R3 powered by a 9V battery through the barrel jack (disregard the USB shown, it's a part of the model and it can't be removed). To ensure a steady 5V supply, I've connected the 5V pin to the positive terminal of the lower power rail of my breadboard, and of course, grounded it with the GND pin to establish a common ground. Now, for the upper power rail, I have a step-down buck converter (not shown in the diagram) connected to a 12V battery (again, it's shown as 9V, but let's just pretend it's 12V).
Both power rails are connected through a common ground.
On the lower power rail, I've hooked up an ultrasonic sensor, powered with a consistent 5V supply, and directly connected it to the Arduino board for the trigger and echo pins. Also, on the upper power rail, I've got two servo motors running off a consistent 6V supply from the buck converter, also directly linked to the Arduino board for their signal pins.
Now, I'm still very much a beginner with this kind of stuff, so I want to hear from the more experienced people here: Does this setup look alright to you? Are there any red flags or potential issues that I should be aware of? And perhaps more broadly, can I keep expanding using this approach, adding more components directly to their respective power rails based on their operating voltages?
Thanks in advance for any insights and advice you can offer!
the rectangular 9V battery will be depleted very quickly by the servos
Less quickly for the one feeding the Arduino, but still probably an hour or so, tops
If your breadboard looks like that, verify that there actually is a connection all the way down the side for your GND. Often, there is a break half way down, and the extra space this image shows implies exactly that.
HTH
It'll work, in principle, but I'm not sure it's all that sensible.
You generally use batteries if portability is required. However, the use of two separate batteries doesn't mesh with that very well, and neither does the use of a fairly small breadboard. So assuming this is a prototype/experimental setup, I'd suggest just powering the Arduino from USB and using a wall-plugged power supply for the motors.
Whether the setup can be expanded, depends on what you want to expand it with. Add a couple of low-power sensors? Sure. Add more powerful motors/steppers/etc? Depends on the specifics of how you've powered that part.
If you intend to do more projects in the future, I'd recommend getting an affordable lab power supply with variable output voltage and current limiting. Very convenient, and they're not too expensive either.
As jim-p said connect the servos directly to the buck converter, not through the breadboard but don't forget a ground wire from 6 volt - (negative) to Arduino GND.
BTW: Is your buck capable of supplying the stall current of 2 servos? Could be more than 2 Amps.
look more closely at the breadboard wiring. IF it has a break, as I suggested it might, then yes, he has a problem. Otherwise, it's referenced. Now, as to the quality of doing your ground reference through a breadboard at all, well, that's a whole other issue, but it will probably work okay - until it doesn't.
